Maybe the PS3 would have a chance at surpassing Xbox 360 for a week or two IF the price cuts and the introduction of the 40 GB model were simultaneous in all the territories... But the schedule is:
5th of October - Europe - price cut on the 60 GB model
10th of October - Europe - 40 GB model introduced
17th of October - Japan - price cut on the 20/60 GB models
18th of October - USA - price cut on the 80 GB model
2nd of November - USA - 40 GB model introduced
11th of November - Japan - 40 GB model introduced
By spreading the sales spikes in this way, they have made it very hard for the PS3 to have a stellar week worldwide. But they have bigger problems than that, it's not like many people are aware of worldwide weekly sales anyway (outside vgchartz).
My Mario Kart Wii friend code: 2707-1866-0957
